What to know about a new PET scan

Before the scan, a tracer such as FDG radiotracer is given, usually through a vein. Cells that use more glucose may collect more tracer, creating areas of increased activity on the images. The CT part shows anatomy, while PET adds information about tissue behaviour. Inflammation, infection and healing can also appear active, so a bright area is not automatically cancer.

Doctors may use PET-CT to look for disease in several body regions, assess treatment response or help choose a biopsy site. It may be useful when investigating lymphoma or cancer of unknown primary. The report is interpreted alongside symptoms, examination, earlier scans and tissue results.

Follow the imaging centre's fasting instructions and tell staff about diabetes, pregnancy, breastfeeding, allergies and difficulty lying still. Wear comfortable clothing and remove metal items if requested. After the tracer is given, rest quietly and limit conversation before imaging. Drink fluids afterwards if your team permits, and follow their instructions about contact with young children or pregnant people.

Tell the team immediately about pain, swelling or redness at the injection site, dizziness or feeling unwell during preparation. After leaving, seek urgent help for breathing difficulty, facial swelling or collapse. Contact the centre if you vomit, cannot complete the scan or have questions about diabetes medicines and fasting.

Why has this scan been requested? Which area is being assessed? How should I manage food, fluids and diabetes medicines? When will the report be available, and which result would change the next step?